Telegraphy.



' BWHD y STATES PATENT OFFICE,

PATRICK'B. .'ELNY, 0F SOUTH ORANGE, NEW JERSEY, ASSIGNDR TO lHE TELEPOSTGPL.NY,OF NEW YORK, N. Y., A. COEPGRATION OF MAINE.

ressorteren".

Speccation ot Letters fatent.

Patented Aue. 25, 1914.

Application area January is, i909. serial no. 472,939.

`which the Jfollowing is a specification.

This invention relates to automatic chemical telegraphy in which eachsignal, whether` a dot or a dash, is initiated by a current impulse ofone polarity and 'terminated by a current impulse of opposite polarity,all the impulses being oi equal duration and'the dots and dashesdistinguished by the interval 'of time elapsing between the transmis--sion of the initiating and vterminating impulses-such interval beinglonger in the transmission of a dash than when a dot is transmitted. Insuch a. system both impulses are recorded in parallel lines on thechemical receiving tape, and the impulses may be sent into the line bfmeans of angularly disposed perliorations ormed in parallel lines in atransmitting tape. Letters Patent No. 07,- 79l, granted October-Bl, 1893disclose a system of this general character. Where the signals aretransmitted at moderate speed over a line of little or no capacity therecord on the receiving tape will be definitely legible, a straight lineconnecting the two marks constituting a dot signal showing much lessangular displacement than a line connecting the two marks constitutingthe record of a dash signal. At higher speeds, however., or over lineshaving considerable electro-static capacity the difference of anglebetween dots and dashes, always a matter of comparison, is not soreadily discernible.

The present invention comprises a inode of operation affording clearlylegible deiinition of the received records whether the line has much orno capacity and comprehends an arbitrary disposition of the dots ormarks upon the receiving tape other than the natural one due only to theregular sequence upon the line ot the current impulses of alternatingpolarity. Thus, if straight lines directly connecting, on the receivingtape, the front ends of the two marks, constituting the record of eachdot signal, are always perpendicular to the tape or inclined toward theJleft; and straight lines directly connecting the trout ends of' therespective pairs of marks constituting the record of dashes, alwaysincline to the right, the definition between dot and dash signalsrecorded outhe receiving tape is` clear and unmistakable irrespective ofthe amount of capacity ot' thc line. Experience has demonstrated thatthis highly desired result may be realized by the simple expedient ofextending beyond its mate and in the direction of travel of thereceiving tape that one of the recording fingers that makes a record ot'the signal-terminating impulse. The extension of such finger in advanceof its mate may be such .as to equal. the space, or the interval oftime,be tween the transmission of the impulse initiating a dot signaland that terminating such signai, thus causing the last impulse of a.dot signal arriving at the receiver to appear on. the tape just as therecord of the first impulse has passed into vertical alinenient with itso that the two dot marks on the tape are in a line perpendicular totheplength of the tape. lf the recording lfinger in question be furtherextended, then the mark produced by it may be in advance of the markproduced by its mate, so that a straight line connecting them willincline to the left. The dash having about three times the length (i. e.interval between impulses) of a dot the angular disposition of the marksu on the receiving tape is well defined an corresponds approximatelyV totwice the-dot length. As dot'and dash lengths are construed relativelythe actual length is, in practice, not material, and as a matter of factin operation of ordinary Morse the dashes made by Morse key, auto-dotand key board transmitters generally fall short of the theoreticallength.

Over a line of very little or no capacity the elements ot letters, dotsand dashes, are respectively of uniform size. The perpendicular positionor slightly reverse angle of the recorded dot marks eliminates all doubtas to the identity of the characters. Over circuits having capacityverification of the reading line is realized in the negative or upperline, as all the tailing in the reading line, theV lower line ofcharacters, is in the direction of bridging the angle between the marksrepresenting dashes, while the tailings of the reverse charactersrepresent and emphasize spacing between letters and words. As every dotand dash is finished with a reversal of current the effect o the staticcurrent is always the same--marking the termination of any succession ofreversals. It will be seen that this system of recording has importantadvantages. It is not necessary to add capacity7 to a circuit for thecompletion of a dash, its boundaries being plainly marked by the twomarks angularly disposed, so that the natural capacity record betu'eenneed not extend to the limit. The last dot or mark oiI the dash leavesno room for doubt. In this Way all lines can be worked upon the basis oftheir natural condition, the extremes calling .for no artificialbalancing, signals of uni- ,iorm size over a line Without capacity beingperfectly plain While those over a. line from moderate to great capacityare recorded in dot marks and actual dash marks.

In the accompanying drawings: Figure l is a diagram indicating atransmitting and receiving station: and Figs. 2, 3, 4, 5 and 6respectively are views showing sections of tape with received signalsrecorded chemically thereon according to the Universal Code: and Fig. 7indicates diagrammatically a section of perforated transmitting tape, asection of receiving tape, and the relative arrangement of therespective transmitting and recording fingers.

Referring now to Fig. l, the transmitter T at X is sending impulses ofequal duration and reverse polarity from the perforated tape t (asalready Well understood) by means of the transmitting brushes or fingersc, f.y At receiving station Y the recording pens or fingers c and Z areresting on the chemically prepared'tape The upper finger' is extendedlin advance of its mate as described. The arrangement may be such as tobring the marks constituting a dot signal in line perpendicular to thetape, and the marks constituting a dash signal Will of necessity beangularly disposed.

idealer Fig. 2 represents a received record free :from static currenteffects on which the dot marks are in line perpendicular to the tape.

Fig. 3 represents a record over a line with slight static capacity.

Fig. et represents a record over a line With considerable capacity.

Fig. 5 represents a 4record over a line hav- No change in atmosphericconditions af- Y eeting the static capacity of the line will aHect theeiiiciency of the receiver,nor Will a change from one Wire to anothercall for any alteration, the method being always adapted to the highestand lowest signaling facility of the wire, from an overhead line of tenmiles, toa long circuit of underground cable.

A chemical tape receiver having two recording fingersone of which makeson the tape in one line a record of the signal initiating impulses, andthe other in a parallel line a record of the signal terminatingimpulses, the latter finger being extended beyond its mate in thedirection of travel ci the tape combined With a transmitter that sendssignal initiating impulses and signal terminating impulses, saidimpulses being of alternating. polarity.

ln testimony whereof, I have hereunto subscribed my name.

PATRICK B. DELANY. Witnesses:

CHAs. E. PERKINS, B. E. HOLLEY.

